1. Fields of the Invention
The present invention relates to an open wrench, and more particularly, to an open wrench with less material required while the strength is maintained.
2. Descriptions of Related Art
The conventional open wrench is disclosed in FIG. 21 and comprises a head 60 having a handle 61 and a driving portion 62 whose thickness is thicker than that of the handle 61. The thicker driving portion 62 is heavy. FIG. 22 shows another open wrench which comprises a head 70 having a handle 71 and a driving portion 72 which includes a first layer 721 and a second layer 722 formed thereon. The thickness of the first layer 721 is the same as that of the handle 71. The second layer 722 is located along the opening of the head 70. The second layer 722 protrudes from the first layer 721. The head 70 meets the standard of German Standard DIN 3113. However, the volume of the head 70 is smaller than the head 60, the wrench cannot output satisfied torque.
The present invention intends to provide an open wrench to eliminate the shortcomings mentioned above.